Magneto Convection of Rotating Nanofluids in Porous Medium:Metals and Semiconductors as Nanoparticles

Present paper investigates the onset of thermal convection of a porous nanofluid layer under the combined influence of rotation and magnetic field using Darcy-Brinkman model which is the modification of the Darcy model where in viscous shear effects and change in viscosity are accounted in momentum equation.In the present model, due to the presence of rotation Coriolis force term and due to the presence of magnetic field Lorentz's force term get introduced in the conservation equations of momentum coupled with the Maxwell's equations. To investigate the combined effect of these forces on the thermal convection of nanofluid layer normal mode technique and Galerkin type weighted residual method is applied. A comparative analysis of the thermal instability of metallic (Cu, Ag) and semiconducting (TiO₂, SiO₂) nanofluids is examined. It is observed that metals are more stable as compared to semiconductors. Further, it is found that silver nanoparticles stabilize the water based fluid more as compared to copper nanoparticles and in semiconductors TiO₂ nanoparticles enhance the stability of the system more as compared to SiO₂ nanoparticles. Stability of the system enhances with the rise in Chandrasekhar number and Taylor number whereas it falls with the rise in porosity. An additional parameter i.e. Darcy number is introduced due to the consideration of Darcy Brinkman model which has a stabilizing effect on the nanofluid layer system.